what is SinACosB equivalent to?

Question

anonymous · Answer

SinACosB

anonymous · Answer

There is a trigonometric identity. Cannot remember what it is. please help me ...

The original question is: Sen(150º)Cos(240) + Cos(150º)Sin(240º)
simplify that please

anonymous · Answer

Sin(150+240)

anonymous · Answer

Ah, what you are looking at there is the rule for sin(a+b).  This cannot be done in two separate parts as you had (SinACosB is pretty meaningless).  Adding the second one makes it sin(390)=sin(30) = 1/2

anonymous · Answer

thanks

anonymous · Answer

$$\sin \left( A \right)\cos \left( B \right)=\left( \sin \left( A \pm B \right) \right)/\left( \pm \cos \left( A \right) \sin \left( B \right)\right)$$

anonymous · Answer

amsp14:
Isn't it
$$\sin(A)\cos(B)=\sin(A\pm B)\mp \cos(A)\sin(B)$$?

anonymous · Answer

yes... I don't see the sign
sorry